1. Field of the Invention
The present invention relates to mats used for erosion control, pipeline protection, crossings, and many other subsea uses, and methods of installing such mats.
2. General Background of the Invention
Erosion control mats have been used for many years to protect soil surfaces such as the banks of water bodies (lakes, rivers, etc.). Such mats have also been used as protection for underwater pipelines.
Patents have issued that are directed to erosion control mats. An example of such an erosion control mat is the Pilaar patent (U.S. Pat. No. 3,597,928). The Pilaar patent relates to an erosion controlling protective surface for a soil mass. The device includes a flexible supporting sheet that can conform to the contour of the soil. Blocks are mounted on the supporting sheet. The mat provides drainage passageways therethrough so that water can pass through the surfacing. Preferably, the surfacing includes a filter and the blocks are secured with the supporting sheet.
The Nelson patent (U.S. Pat. No. 3,386,252) shows a rip rap structure that employs concrete blocks connected together.
Cables are employed to hold blocks together in the Landry patent (U.S. Pat. No. 4,227,829) to form a matrix of blocks.
The Crow patent (U.S. Pat. No. 4,375,928) shows rows of blocks held together by a continuous wire cable which is embedded in each block.
The Waters patent (U.S. Pat. No. 4,683,156) shows an erosion control blanket of segments. The segments are said to be of concrete placed into shells. The segments are held together with a rope network. Openings in the shells provide points of entry for the ropes.
The Rudloff patent (U.S. Pat. No. 5,484,230) provides a concrete block revetment system for soil erosion prevention. The system of the Rudloff patent provides concrete blocks that are cable interconnected to form a matrix. The matrix of blocks overlies and holds in place a layer of permeable geotextile overlying a protected soil area.
The Angel patent (U.S. Pat. No. 6,027,285) entitled “Mat Installation” shows cable connected erosion control blocks that can be used over pipelines. Other patents issued to Angel include numbers U.S. Pat. Nos. 5,722,795; 5,846,023; and 5,944,449.
The Landry patent (U.S. Pat. No. 4,486,120) provides a spreader bar for the installation of soil erosion prevention mats.
The Daniel patent (U.S. Pat. No. 6,406,217) provides a lifting and placing device for seabed mats.
Other patents possibly relevant to the construction and use of mats for erosion control, pipeline protection, crossings, and other subsea uses can be seen in the following table, the listing being chronological and otherwise of no significance. Each of the patents listed in the table (Table 1) is hereby incorporated herein by reference.
TABLE 1Issue DatePat. No.TitleMM/DD/YYYY3,386,252Rip Rap Structure Device09/08/19663,597,928Erosion Control08/10/19714,227,829Soil Erosion Preventing Blocks10/14/19804,375,928Flexible Concrete For Soil Erosion03/08/1983Prevention4,486,120Spreader Bar For Soil Erosion Prevention12/04/1984Mats4,683,156Flexible Blanket07/28/19875,484,230Concrete Block Revetment System For01/16/1996Soil Erosion Prevention5,722,795Non-Abrasive Subsea Mat03/03/19985,846,023Non-Abrasive Subsea Mat12/08/19985,944,449Non-Abrasive Subsea Mat08/31/19996,027,285Mat Installation02/22/20006,406,217Lifting and Placing Device for Seabed06/18/2002Mats8,858,118Erosion Control Mat System10/14/2014